Clock synchronizer



April 14, 1953 MAERZ 2,634,575

CLOCK SYNCHRONIZER Filed June 5, 1947 5 Sheets-Sheet l INVENTOR ATTORNEY 0 Henry Maep BY O le/14, 641W 9 April 14, 1953 H. MAERZ CLOCKSYNCHRONIZER Filed June 3, 1947 3 Sheets-Sheet 2 INVENTOR Hen/n Maefi BY 5 W ATTORNEY n79 April 14, 1953 M z 2,634,575

CLOCK SYNCHRONIZER Filed June a, 1947 3 Sheets-Sheet 5 INVENTOR bm y Maez z ATTQ RNEY3 Patented Apr. 14, 1953 CLOCK SYN CHRONIZER Henry Maerz, Brooklyn, N. Y., assignor to Self Winding Clock Company, Inc.,'a corporation of Delaware Application June ,3, 1947, Serial No. 752,110

1 Claim. 1

This invention relates to clock synchonizers and more particularly to single stroke synchronizers which reset the clock hands by direct rotation thereof, and is especially adaptable for use in a subsidiary clock system.

Synchronizers of the above type periodically reset the clocks to a predetermined position by forcibly rotating a hand thereof with a single stroke of a synchronizing lever actuated by an electromagnet in the subsidiary clock which in turn is energized by the closing of a circuit in a master clock, such single stroke synchronizing action accomplishing the resetting in a single quick motion.

A friction coupling or clutch interposed besensitive balance mechanism may tween the clock hand and the wheel and other escapement offer sufficient resistance to transmit severe torque through the gear train to such sensitive parts with possible injury thereto, as the result of such sudden stroke. While loosening such friction coupling or clutch would help to protect the delicate escapement mechanism, it would allow the hand to slip especially if it is large and heavy, thereby resulting in an unreliable time indication during the hour.

In addition, if the synchronizing electromagnet in the subsidiary clock should remain energized, due to some defect in the circuit thereof, or if a defect in the master clock should cause the synchronizing electromagnets in all the subsidiary clocks to remain energized, the braking effect of the synchronizing lever on the clock hand transmitted through the friction coupling to the escapement mechanism would cause the clock or clocks to stop. Since common clock escapements, as for instance those of pendulum clocks and balance wheel clocks, do not automatically resume operation when the oscillating members are at rest, special and costly self-starting devices are required or manual restarting becomes necessary. This is a very serious problem in subsidiary clock systems having a large number of clocks, some of which may be relatively inaccessible, for it requires a great deal of time and considerable cost and inconvenience to restart each clock.

It is among the objects of this invention to provide a clock synchronizing device that is reliably actuated by a single impulse from .a re- 2 nism thereof or of stalling the clock, should the operating instrumentality either of an individual clock or of a master clock controlling a whole battery of clocks be frozen or jammed.

According to the invention, a driving member is rigidly connected to the arbor driving the clock hand being synchronized, the latter being affixed to a shaft idly mounted on one end of said arbor. A driven member afixed to said shaft is normally operatively connected to said driving member by resilient means, thereby rotating said shaft and the clock hand thereon. Periodically a synchronizing impulse energizes an electromagnet in the clock to pivot a synchronizing lever which sets the clock hand to a predetermined position and at the same time disconnects the driven member from the driving member. When the synchronizing period is over, the lever will pivot back to its original position and the driven member will again be operatively connected to the driving member to continue the rotation of the clock hand.

In the accompanying drawings in which are shown one or more of various possible embodiments of the several features of the invention,

Fig. 1 is a front elevational view of a clock illustrating one embodiment of the synchronizing mechanism,

Fig. 2 is a fragmentary view on a larger scale showing the synchronizing mechanism,

Fig. 3 is a sectional view taken along line 3-3 of Fig. 2,

Fig. 4 is a perspective view of a portion of the synchronizing mechanism showing the sleeve on which is aiiixed the clock hand, the synchronizing stop cam and the driven member,

Fig. 5 is a fragmentary front elevational view illustrating a second embodiment of the synchronizing mechanism,

Fig. 6 is a fragmentary sectional view taken along line 6-45 of Fig. 5,

Figs. '7 and 8 are perspective views of a portion of the second embodiment of the synchronizing mechanism, and

Figs. 9, 10 and 11 are diagrammatic views of a portion of the synchronizer mechanism in various stages of movement of the clock hand.

Referring now to the drawings, in Figs. 1 to 4 is shown a preferred embodiment of the syn- Chlol'liZlllg device especially suitable for clocks in which the second hand is not mounted on the same arbor as are the minute and hour hands.

The second hand arbor H is journalled in bearing openin s in the front and rear panels of the clock and is driven by a gear train which is in itself conventional and will not be described inasmuch as it forms no part of this invention.

Arbor H has a reduced portion I2 which extends outward from bearing opening 13 in front panel 14, the reduced portion being threaded at its end as at it. A disk-shaped driving memher it having a hub i? is affixed on reduced portion l2 by means of a set screw I8 threaded in said hub, the latter abutting the shoulder is formed at the root of said reduced portion l2.

Rotatably mounted on reduced portion i2 is a shaft 2| in the form of a sleeve, the bore 22 of which is reduced near one end to form a shoulder 23. which is threaded on the end 15 of reduced portion l2 and which abuts against shoulder 23 of sleeve 21. Affixed on sleeve 2| at the outer end Sleeve 2| is retained .by means of a nut 24.

22 thereof is a second hand 25, while asubstantially annular driven member 2% of resilient spring material is aflixed by means of an arm 2? unitary therewith and extending radially in- Iward therefrom to the inner end 2| of sleeve 2 i A tooth or projection 28 on one face of member 28 is urged by the resiliency of said member against one of the radiating grooves 2% forming a ring as near the periphery of disk it. A

reversely turned flap 29, the front wall 29 of which is bent outward, is formed unitary with annular member 26 for the purpose hereinafter set forth. A synchronizing stop cam 3| having a sleeve 3| rigid therewith, afiixed to sleeve M as by force fit, enables sleeve 2| and clock hand 25 .to be rotated to a predetermined position. Cam 3| is eccentrically mounted on the sleeve the right angled extension 38 of which has a roller A l thereon rotatably mounted as at 2-5 and a carnming hook A6 affixed to the free end thereof by screws All, the end of said hook being beveled as at 8.

a lever 31. An electromagnet 39 is supported from the frame by a bracket 49 and has an armature pivoted at one end to the frame as at 32 and having its free end pivotally connected to one end of a pitman 53, the other end of the pitman 43 being pivotally connected to an arm 38 extending from lever 31.

In normal operation, sleeve 2i carrying second hand is driven by second hand arbor H by means of the driving member. 16 on the latter and driven member 26 with tooth 28 thereon, the resiliency of annular driven member 25 being sufficient to urge the projection or tooth 28 into frictional engagement with ring 26' on disk it and thus insure positive drive of sleeve 2|.

At predetermined intervals a synchronization impulse is delivered to electromagnet 39 fromsome remote source (not shown). Energization of electromagnet 39 will cause its armature A! to quickly pivot upward about its pivot d2, thereby raising pitman 3 and pivoting synchronizing lever 36 downward to drive roller it against stop cam 3| causing the latter to rotate sleeve 2| until the front edge of arm 36' is flush with the straight edge 32 of stop cam 3|. This will occur when the second hand 25 afiixed to the outer end 22' of sleeve 2| is indicating the 60 minute position. As sleeve 2| is rotated, the projection or tooth 28 will ratchet over grooves 28 of ring 26 and transmit but little shock to the escapement mechanism. As synchronizing lever 36 approaches the limit of its stroke, the beveled edge -68 of camming hook 56 will contact theout- 'wardly bent front wall 29' of flap 29 and as the Also pivotally mounted on said stud and affixed to said synchronizing lever 36 is 4 lever 35 continues its movement and hook 46 is urged further into flap 29, the resilient annular member 26 will be urged away from disk It, withdrawing tooth 28 from ring 20, thus permitting the second hand arbor H to turn freely as the gear train is no longer affected by the braking action of the synchronizing lever. As there is no longer any coupling between sleeve 2| and the gear train, there is no danger of the latter being stopped in the event that electromagnet 39 should remain energized.

A second embodiment of this invention shown in Figs. 5 to ll of the drawings is especially suitable for clocks in which the second, minute and hour hands are mounted coaxially with each other and is illustratively shown as applied to a pendulum type clock.

encompassing the extending end 51 of arbor 50 on which it is idly mounted. Affixed to said shaft 58 is a plate or disk Eli having a ratchet pawl $2 pivotally mounted on a stud 52 on one face thereof. Ratchet pawl 6| is urged against the teeth 54 of ratchet wheel 53 by a leaf spring 63 bent over the disk as at 64 and afiixed thereto by a stud 65 extending laterally from said disk on the opposite side to which ratchet 6! is pivotally mounted. Shaft 58 is journalled in and has a reduced end 56 which extends from a sleeve ti unitary with a support plate 88 affixed to the frame of the clock as at 52.

The bore 69 of sleeve 6'! is reduced at one end to form a shoulder it against which the shoulder l formed at the root end of the reduced portion 56 of shaft 53 abuts. This prevents axial movement of shaft 58 which might cause ratchet pawl 65 to slip ofi the teeth 54 of ratchet wheel 53.

Idly mounted on sleeve 67 is a gear '12 having -a sleeve '53 unitary therewith and coaxial with and encompassin sleeve 67. A gear 14 is idly mounted on sleeve '53 and has a sleeve 75 unitary therewith which is coaxial with and encompasses sleeves 6 and 73. Gears l2 and it which drive the minute and hour hands respectively are in turn driven by a conventional gear train which will not be described inasmuch as it forms no part of this invention.

Coacting with the said stud -25 and ratchet pawl iii is the synchronizing lever l8 pivotally mounted on a stud 79 extending laterally from the frame 52 of the clock. Also pivotally mounted on said stud l9 and affixed to said synchronizing lever 78 is a lever to having a yoke 8i extending therefrom. Lever Si] is afixed to lever ?8 by a screw 82 which extends through an arcuate slot 83 in lever 35 to permit adjustment of the latter with respect to lever it.

An electromagnet 84 is supported from the frame by a bracket 85 and has an armature 86 pivoted at one end as at 87. The armature has a stud 83 extending from the free end thereof which is straddled by the arms 89 of yoke 8| whereby movement of the armature 35 will be transmitted to lever iii. A yoke 93 at the free end of lever i8 coacts with stud 65 when the lever is pivoted,

as will be hereinafter described. Extending from the closed portion 9! of the yoke is a ratchet pawl release arm 52 which is curved at its free end and has a shoe 93 unitary therewith which will contact the free end El of ratchet pawl 5% when the lever 18 has been pivoted to pivot the ratchet pawl about its stud 52 and to disengage it from the ratchet wheel.

In normal operation shaft 58 carrying second hand T5 is riven by second hand arbor 59 by means of ratchet wheel 53 on the latter, the tension of spring 53 being sufhcient to urge ratchet pawl 6i into engagement with the teeth 54 oi ratchet wheel and insure positive drive of said shaft 5%.

At predetermined intervals a synchronizing impulse is delivered to electromagnet '8 from some remote source (not shown). Energization of electromagnet 3 will cause its armature to be quickly pivoted thereby pivoting synchronizing lever '58 downward and driving the yoke end Bil of lever '58 against stud which has been revolving around shaft 58 as the latter rotates.

If for any reason the clock should be, for example, 15 seconds slow when the synchronizing impulse is received, the yoke end at of lever itwould be forced. against stud 65 which at this timwould be in the position shown. in Fig. 10. As disk Gil is only coupled to ratchet wheel 53 by the tension exerted on ratchet pawl iii by spring the force of the synchronizing blow of yoke t0 against stud as will rotate disk he in a clockwise direction and the ratchet pawl 6i will ride over the teeth of ratchet Wheel 53 until the yoke end as or". the lever S straddles stud which would be in the position shown in Fig. 11. In this position the second hand of the clock will indicate the 60 minute position. If the clock should he say 15 seconds fast when the synchronization impulse wasreceived, lever 18 and stud 85 would be in the position shown in Fig, 9 and disk would be rotated in a counterclockwise direction to the position shown in Fig. 11 to properly set the second hand. If the clock is on time when the synchronizing impulse is received, since stud 65 and lever '58 would be in the position shown in Fig. 11, no movement could be imparted to disk Gil and shaft 58 by lever 18 inasmuch as the stud es would already be in the proper position for such time indication. It is to be noted that the symmetrical teeth as on ratchet wheel 53 permit ratchet pawl iii to ride thereover in both a clockwise and counterclockwise, thus permitting synchroni ation when the clock is fast or slow.

As yoke 5i] is driven against stud $5, shoe 93 will be urged against the free end 6! of ratchet pawl GE and will pivot the latter against the tension of spring 63 so that it no longer engages the teeth on ratchet wheel 53. This will occur at each synchronizing impulse and thus permit the second hand arbor 58 to turn freely and as there is no longer any coupling between disk 60 and shaft 58, there is no danger of the escapement mechanism being stopped in the event the impulse to electromagnet 84 is unduly prolonged.

Although the coupling between the driving member and driven member of either of the embodiments herein is disengaged only when the synchronizing lever has reached the end of the stroke, it is to be understood that it would be a relatively simple expedient to modify the construction herein slightly so that the coupling could be disengaged at the beginning of the stroke of the synchronizing lever. It is important, however, that such disengagement occur no later than the end of said stroke for if such was the case, the continued braking effect of the synchronizing lever transmitted to the escapement mechanism of the clock would stop the latter with the attendant difficulties heretofore set forth.

Inasmuch as it takes only a relatively small amount of power to drive the clock hand, the resilient member coupling the driving member and the driven member need exert but a small tension to ensure positive coupling. In the case of the first embodiment herein shown, the synchronizing action drives the hand in a clockwise direction and therefore does not have any braking effect on the escapement mechanism until the end of the stroke, at which time however the coupling is disengaged. In the case of the second embodiment, although the hand would be moved in a counterclockwise direction if it was fast, it is moved so quickly to its proper position that the baking effect, which only lasts for a very short interval, is not sufiicient to stall the pendulum, the inertia of which keeps it oscillating for several seconds even after the clock is stopped.

It can thus be seen that the use of the device herein will insure positive drive of the clock hand, yet permit resetting of the latter at predetermined intervals without danger of injury to or stoppage of the escapement mechanism of the clock, thereby eliminating the resulting inconvenience that such stoppage or breakage would cause,

As many changes could be made in the above construction, and many apparently widely different embodiments of this invention could be made without departing from the scope of the claim, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

In a clock of the type comprising a frame, a gear train supported by said frame, an arbor journalled in said frame and driven by said gear train and a clock hand; the combination therewith of a disk afiixed to said arbor and having a plurality of radially extending grooves forming a ring on one face thereof, a shaft rotatably mounted on said arbor and carrying said clock hand, a cam and a resilient ring member coaxial with said shaft, said resilient ring member having a tooth on one face thereof normally urged into engagement with the ring on said disk, a lever pivoted on said frame, a roller on said lever, means to pivot said lever and urge said roller against said cam to rotate the latter and said clock hand operatively connected thereto, a flap on said resilient ring member in juxtaposition to said tooth, a camming hook affixed to said lever, said camming hook engaging said flap and camming said resilient ring member outward, thereby disengaging said tooth from said ring when said lever has been pivoted to the limit of its stroke.

HENRY MAERZ.

References Cited in the file of this patent UNITED STATES PATENTS Number 

